1. Field of the Invention
The present invention relates to a buckle whose female receptacle and male latch can be coupled to each other, and more particularly, to a buckle that includes a male latch having an improved shape.
2. Description of the Related Art
Generally, a buckle has been widely used in a waist belt, a knapsack for climbing, or a shoulder strap of a school bag and includes a female receptacle and a male latch.
The buckle includes a female receptacle and a male latch that are detachably connected to each other. A pair of hooks are formed at the male latch and a receiving part having elasticity is formed at the female receptacle to receive the hook of the male latch. Each of ends of the female receptacle and male latch is provided with a connector to be coupled to an end of the belt or shoulder strap (hereinafter, referred to as “belt”).
FIGS. 1 to 3 show various constructions of conventional buckles. The conventional buckles are comprised of female receptacles 12a, 12b and 12c and male latches 11a, 11b and 11c respectively.
A guide projection is formed at the middle of each of the male latch 11a, 11b and 11c and a pair of hooks are formed at both sides thereof.
Each of the female receptacles 12a, 12b and 12c is provided with an insertion part (not shown) into which the guide projection and hooks are inserted. A receiving part is formed at both sides of the female receptacle so as to be connected to the hooks of the male latch.
On the other hand, the female receptacle and male latch can be connected with the belt by the connector formed at ends thereof.
Operation of the above conventional buckle will be explained below.
The male latches 11a, 11b and 11c and female receptacles 12a, 12b and 12c are made of plastic for elasticity. Accordingly, arms 14a, 14b and 14c and projected parts 13a, 13b and 13c of the hooks of the male latches are inserted into the receiving parts of the female receptacles while they are deformed toward guide projections at the middle thereof. In this time, when the hook is located in the receiving part of the female receptacle, the hook is restored to an original state and thus the projected part 13a, 13b and 13c is engaged with a hooked projection of the receiving part. Thus, the male latch and female receptacle are coupled to each other.
To the contrary, when the hook of the male latch 11a, 11b or 11c located in the receiving part of the female receptacle 12a, 12b or 12c is pushed inward by a user, the projected part 13a, 13b or 13c of the hook is released from the hooked projection of the receiving part, thereby allowing the female receptacle and male latch to be separated from each other.
However, in the conventional buckle, a projected surface of the projected part 13a, 13b or 13c of the hook to be contacted to the hooked projection of the receiving part is formed at one or two side surfaces. Accordingly, coupling force between the male latch and female receptacle is weak and thus the male latch may be separated from the female receptacle even by low external pressure.
For example, as shown in FIG. 1, it is disclosed in the registered Korean Patent publication No. 0452565 that a projected part 13a of a hook of a male latch 11a is extended likely to surround an outer surface of an arm 14a with different heights. The hook of the male latch 11a includes a ‘V’ shaped protruded surface that surrounds only an upper surface of the arm 14a, that is, the whole first surface, and both side surfaces, that is, very small portions of second and third surfaces of the arm. A projected part 13b of a hook of a conventional male latch 11b shown in FIG. 2 is extended in the same height from the both side surfaces, that is, second and third surfaces of the arm. In addition, a projected part 13c of a hook of a conventional male latch 11c shown in FIG. 3 is formed of a rectangular protruded surface extended in the same height from an upper surface, that is, a first surface of the arm 14c. 
In other words, the projected parts 13a, 13b and 13c of the conventional buckles are projected from one or two side surfaces and thus contact surface with the hooked projection is small. Accordingly, there is a problem that coupling force between the projected part and hooked projection is reduced.
In addition, in the above conventional buckles, the projected part of the male latch is formed of only one or two protruded surfaces and thus force is less distributed. Accordingly, when excessively strong force is applied from the belt, the projected parts 13a, 13b and 13c, or the hooked projection of the female receptacle may be damaged to cause the buckle to be released.